Scalable, massively parallel process for making micro-scale particles

ABSTRACT

A method of fabrication produces one or more functional microparticles using a parallel pore working piece. In one embodiment, the method forms a particle that includes a segment for the oxidation of a biofuel (such as glucose) and the reduction of oxygen. The particle may be synthesized in a structure with defined and parallel, uniform, thin pores that completely penetrate the structure. Further, the functional microparticle may be configured to reside in a human or animal body or cell such that i t may be self-contained fuel cell having an anode, a cathode, a separator membrane, and a magnetic component. In other embodiments, the functional microparticles may deliver energy or therapeutic materials in the body.

CROSS REFERENCE

This application claims priority under 35 U.S.C. 119(e) to U.S.Provisional Patent Application No. 62/068,083 (incorporated by referencein its entirety) filed on Oct. 24, 2014, entitled “SCALABLE, MASSIVELYPARALLEL PROCESS FOR MAKING MICRO-SCALE PARTICLES THAT INCORPORATE AFUEL CELL.”

FIELD

Disclosed embodiments are directed to functional microparticles andmethod of fabrication of functional microparticles.

SUMMARY

Disclosed embodiments are directed to functional microparticles andmethods of fabrication of functional microparticles using a parallelpore working piece. For the purpose of this specification, functionalmicroparticles are defined as devices with one dimension less than fiftymicrons in length, and which exhibit functionality such as the abilityto generate electrical current (e.g., as a fuel cell), radiofrequencywave generation (e.g., as a spin-transfer nano-oscillator), or carry atherapeutic payload (e.g., as a drug delivery vehicle), or delivertherapeutic energy (e.g., as a magnetizable particle exposed to analternating magnetic field), or a combination of such functionalities.

In accordance with at least one embodiment, such a functionalmicroparticle may be configured to reside in a human or animal body orcell. The functional microparticle may be a self-contained fuel cellhaving an anode, a cathode, a separator membrane, and a magneticcomponent.

In accordance with at least one embodiment, such a device may includesegments for the oxidation of a biofuel (such as glucose) and thereduction of oxygen.

In accordance with at least one embodiment, the particle may besynthesized in a structure with defined and parallel, uniform, thinpores that completely penetrate the structure.

BRIEF DESCRIPTION OF THE FIGURES

The detailed description particularly refers to the accompanying figuresin which:

FIGS. 1-8 collectively illustrate a process for the scalable synthesisof a single functional microparticle, wherein the process is shown as across-section of a parallel pore working piece, in accordance withdisclosed embodiments.

FIG. 1 illustrates fabrication operations of preparing a parallel poreworking piece for electroplating in accordance with the disclosedembodiments.

FIG. 2 illustrates fabrication operations for electrodeposition of aconductive layer into pores of the parallel pore working piece byexposing the open pore side of the parallel pore working piece to anelectrolyte in accordance with disclosed embodiments.

FIG. 3 illustrates fabrication operations for electrodeposition of ananode onto the conductive pore-sealing layer, in accordance withdisclosed embodiments.

FIG. 4 illustrates fabrication operations for vacuum-assisted filling ofa polymer, ceramic, or composite separator membrane into the pores ofthe parallel pore working piece and onto the previously deposited anode,in accordance with disclosed embodiments.

FIG. 5 illustrates fabrication operations for widening the parallel poreworking piece pores by etching the parallel pore working piece material,in accordance with disclosed embodiments.

FIG. 6 illustrates fabrication operations for generating an insulatingtube within the pores of the parallel pore working piece, in accordancewith disclosed embodiments.

FIG. 7 illustrates fabrication operations for performing deposition of acathode in accordance with disclosed embodiments, wherein anoxygen-reducing agent is dispersed in a separator membrane material thatallows the passage of a fuel substrate (e.g., glucose) but inhibits thepassage of oxygen molecules.

FIG. 8 illustrates release of the particles from the working piece,which has been etched away, in accordance with disclosed embodiments.

DETAILED DESCRIPTION

For the purposes of this description, a fuel cell is provided as anexample of a functional microparticle. It is understood that many or allof the processes specified herein may apply to the production anddescription of functional microparticles other than fuel cells, whetheror not the term “fuel cell” is specifically used in the description.

Fuel cells are devices that convert chemical energy into electricalenergy via the catalysis of reduction and oxidation reactions. Glucosefuel cells have been proposed as useful devices for powering electronicsinside the bodies of humans and other animals.

Several investigators have performed experiments demonstrating theapplication of implantable glucose fuel cells in various animals,including dogs, sheep, rats snails, lobsters, and cockroaches. Some ofthese examples are reviewed in the publication “Towards glucose biofuelcells implanted in the human body for powering artificial organs:Review”, by Serge Cosnier, Alan Le Goff, and Michael Holzinger, inElectrochemistry Communications, Volume 38, pages 19-23, 2014(incorporated herein by reference in its entirety).

The processes involved in a fuel cell placed in the body include theoxidation of a fuel material in the body at an anode, and the reductionof oxygen at a cathode. In an implantable glucose fuel cell, the fuelmaterial being oxidized is glucose. Other types of fuel cells mayoxidize other materials. Connecting the anode and cathode surfacesacross a resistive load enables the flow of electrons, which can poweranother device or component of a device or activate one or morebiological cells in the body (e.g., neurons, muscle cells).

Disclosed embodiments provide a device comprised of a particulate fuelcell that can reside in a human or animal body or cell, and a processfor making such devices. This device may be a self-contained fuel cellhaving an anode, a cathode, a separator membrane, and a magneticcomponent. The device, in the form of a particle, may include segmentsfor the oxidation of a material in the body (such as glucose) and thereduction of oxygen.

In accordance with at least one embodiment, the particle may besynthesized in a structure with defined and parallel, uniform, thinpores that completely penetrate the structure 100, as illustrated inFIG. 1.

One example of the structure 100 may be a parallel pore working piececontaining pores. The terms “working piece” and “parallel pore workingpiece” are intended to refer to a template that is used to fabricateparticles, said template later being either discarded or re-used.

In one embodiment, this parallel pore working piece may be an anodizedaluminum oxide nanoporous filter membrane. In another embodiment, theparallel pore working piece may be a polycarbonate track etched filtermembrane. An important aspect of the parallel pore working piece is thatit is a component containing many pores.

In one embodiment in which the working piece is an anodized aluminumoxide nanoporous filter membrane, the pore density may be as large asone billion pores per square centimeter. Because the working piececontains many pores, and because the method used for making fuel cellsusing such a working piece addresses many pores at a time, the method ismassively parallel. As a result, the method may simultaneously generatebillions of functional microparticles, with each pore of the parallelpore working piece containing a single functional microparticle.

In accordance with at least one embodiment, a parallel pore workingpiece may be implemented using an Anodic Aluminum Oxide (AAO) filtermembrane. A method for making AAO filter membranes with uniform,parallel pores was taught by H. Masuda, K. Yada, and A. Osaka, in theirpublication “Self-ordering of cell configuration of anodic porousalumina with large-size pores in phosphoric acid solution,” published inthe Japanese Journal of Applied Physics, Volume 37, 1998 (incorporatedherein by reference in its entirety).

The AAO may be used as the working pieces for generating fuel cells, theresulting fuel cells may be cylindrical in shape. In one embodiment ofthe invention, the fuel cell may contain material layers nested withinone another.

FIGS. 1-8 collectively illustrate a process for the scalable synthesisof a single microwire glucose fuel cell, wherein the process is shown asa cross-section of the parallel pore working piece 100 and singlemicrowire fuel cell. For the purpose of this disclosure, the term“microwire” is defined as a structure where the radius is less thanfifty microns.

As illustrated in FIG. 1, the fabrication of the functionalmicroparticle may begin at operation 10. FIG. 1 illustrates that theapplied conductive layer 110 seals an opening of the pores of theworking piece. Sealing one side of the working piece may be accomplishedby applying a metal film 110 to one side of the parallel pore workingpiece. Said application also prepares the working piece forelectroplating.

In accordance with at least one disclosed embodiment, a pore wettingprocess may be performed by submerging the entire parallel pore workingpiece in water and applying sonication to the parallel pore workingpiece. During the pore wetting process, the act of sonicating thetemplate provides the necessary mechanical energy for a solution toenter the potentially narrow diameter pores of the working piece. In oneembodiment of the disclosure, the wetting process overcomes the surfacetension which may exist at the openings of the pores. When surfacetension is high near the pore openings, the pore wetting processfacilitates the entry of liquid into the pores of the working piece. Theapplication of a metal film 110 to one side of the parallel pore workingpiece may result in a structure composed of parallel pores spanning thelength of a working piece, where the pores are sealed closed on oneside.

Further fabrication may proceed as illustrated in FIG. 2, wherein, at20, electroplating a conductive layer 120 into the pores of the parallelpore working piece. With sealed pores on one side, a conductive layer120 may then be electroplated into the pores of the working piece, asillustrated in FIG. 2.

FIG. 2 illustrates fabrication operations for electrodeposition of aconductive layer 120 into pores of the parallel pore working piece byexposing the open pore side of the parallel pore working piece to anelectrolyte. Magnetic materials may be deposited in this operation inorder to confer functionality.

The conductive layer 120 acts as a conductive surface for furtherelectrodeposition and processing, and/or may also act as a magneticmaterial segment for magnetic field manipulation of the functionalmicroparticle. The magnetic material segment may be composed of aferromagnetic material, such as iron, nickel, or cobalt. The magneticmaterial segment may be composed of a paramagnetic or superparamagneticmaterial, such as magnetite or maghemite. The magnetic manipulation mayoccur in the course of the fabrication process, for example, in order tomove particles from one section of a chamber to another. As a result ofthe above-described fabrication methodology, disclosed embodiments maybe used to produce a device wherein a magnetic iron-palladium segment120 is attached to the platinum anode 130. In one embodiment, theiron-palladium segment is grown, and is in direct contact with theelectrically conductive sealing layer 110 of the working piece. Thisiron-palladium segment 120 may be composed of any electricallyconductive layer.

At 20, electrodeposition into the pores of the working piece may beaccomplished by exposing the open pore side of the membrane to anelectrolyte (for example, a nickel plating solution consisting of 1.1Mnickel sulfate hexahydrate, 0.2M nickel chloride hexahydrate, and 0.75Mboric acid). In electroplating materials onto the side of metal film 110inside the pores of the parallel pore working piece 100, as taught inthe publication “Preparation and Electrochemical Characterization ofUltramicroelectrode Ensembles”, Penner et al. published in AnalyticalChemistry, Volume 59, pages 2625-2630, 1987 (incorporated by referenceherein in its entirety), the electroplating process may fill the poresentirely with the material being plated, or may partially fill the poreswith the material being plated.

The operation performed at 20 may involve the electroplating of apalladium-iron alloy 120, as taught by B.-Y. Yoo, et al. in theirpublication “Electrochemically Fabricated Zero-Valent Iron, Iron-Nickel,and Iron-Palladium Nanowires for Environmental RemediationApplications”, in Water Science & Technology, Volume 55(1-2), pages149-156, 2007 (incorporated by reference herein in its entirety).

Fabrication operations may then proceed to 30, illustrated in FIG. 3, atwhich electrodeposition of an anode 130 onto the electrodepositedconductive layer 120 is performed.

In one embodiment, the anode is made of platinum. In accordance with atleast one embodiment, iron-palladium 120 may be deposited. This platinumanode layer 130 may also fill the width of the pore. The iron-palladiumis an example of a magnetizable material that may be used to propel orposition the particle using magnetic fields. In the interest of brevity,it is understood that layer 130 may represent a combination ofmaterials, either deposited in a single operation (for example by usingan electroplating solution with multiple metals), or in multipleoperations (for example, by successively using electroplating solutionswith multiple metals).

It is understood that the deposited metallic layers may be arrayed toform a spin-torque nano-oscillator or similar spintronic device, whichconverts electrical current into radiofrequency waves. It is understoodthat similarly deposited layers may confer diverse functionality, forexample by acting as diodes, rectifiers, transistors, resistors,capacitors, etc.

Fabrication operations may then proceed to 40, as illustrated in FIG. 4,at which deposition of a polymer, ceramic, or composite separatormembrane 140 may be performed into the pores of the parallel poreworking piece 100, and onto the previously deposited layer 130. Saiddeposition may be performed with vacuum-assisted filling, as taught byX. Chen, S. Li, C. Xue, M. J. Banholzer, G. C. Schatz, and C. Mirkin, intheir publication “Plasmonic Focusing in Rod-SheathHeteronanostructures,” published in the journal ACS Nano, Volume 3,Number 1, pages 87-92, 2009 (incorporated by reference herein in itsentirety).

In a fuel cell, a separator membrane operates as a barrier, separatinggases generated at the anode and cathode of the fuel cell. The separatormembrane also acts to electrically insulate the anode from the cathodeand prevent the fuel cell from shorting between the anode and cathode.This separator membrane may allow the passage of a fuel material (e.g.,glucose) but inhibit the passage of oxygen molecules. In at least oneembodiment, vacuum-assisted filling may be performed by depositing adiluted polymer separator membrane material (for example, Nafiondissolved in a solvent) into the open pores of the parallel pore workingpiece. Nafion has been previously studied as a separator membrane forglucose fuel cells, as taught by Benjamin I. Rapoport, Jakub T.Kedzierski, and Rahul Sarpeshkar in their publication entitled “AGlucose Fuel Cell for Implantable Brain-Machine Interfaces,” in PLoSONE, Volume 7(6), e38436, 2012 (incorporated by reference herein in itsentirety).

Some of the materials used in the fuel cells may begin as liquids ordispersions, becoming solids in the process of making the fuel cells. Inone embodiment, a relevant fuel cell material may be dispersed in asolvent, forming a solution. This process may useful for the depositionof any layer in the fuel cells, including the layers depicted in FIGS.1, 2, 3, 4, 6, and 7. A liquid volume of this solution containing arelevant fuel cell component material may be deposited onto the openpores of the working piece. By depositing a the relevant fuel cellcomponent in a solvent on the open pore side of the working piece (theside of the working piece that is not sealed), placing the working piecein a vacuum chamber, and evacuating the chamber, the solvent may beevaporated, leaving the relevant fuel cell material deposited in thepores of the working piece. In one embodiment, the vacuum is applied toall sides of the working piece.

Applying vacuum to the parallel pore working piece may perform at leasttwo functions. One function is to draw the deposited separator membrane140 solution into the pores of the parallel pore working piece. Anotherfunction of the vacuum-assisted filling operation is to evaporate thesolvent in which the separator membrane 140 material (polymer, ceramic,or composite) is dissolved. Thus, the vacuum process serves to pull asolution, containing a solute and a solvent, sitting on the open poresof the working piece and allow for deposition of the solute in the poresof the working piece as the solvent is evaporated. The result is thatthe solute remains, and is drawn into the pores of the working piece dueto the applied vacuum. The result of this vacuum-assisted filling is aset of cylinders 140, 170 within the same pore, these ensembles ofcylinders being made massively parallel using pores of the parallel poreworking piece 100.

Fabrication operations may then proceed to 50, as illustrated in FIG. 5,at which the pores of the parallel pore working piece are widened byetching 150 the parallel pore working piece material 100. In FIG. 5,item 150 refers to the process of widening the pores of the workingpiece by chemically etching the working piece pore walls. During theetching process 150, the pores of the working piece are enlarged.Etching the pores to increase pore diameter, resulting in a gap betweenthe walls of the pores and the layers of deposited materials 120, 130,140. In at least one embodiment, this operation 50 may be accomplishedusing an aqueous solution of sodium hydroxide to etch the pores of anAAO parallel pore working piece 100.

In at least one disclosed embodiment, the sodium hydroxide may etch thefull length of the pores, making them 10% to 50% wider than the originalpore diameters. Etching the pores of the working piece does not involveetching the layers deposited into the pores of the working piece 120,130, 140, 170.

Fabrication operations may then proceed to 60, as illustrated in FIG. 6,at which point an insulating tube 160 is generated within the pores ofthe parallel pore working piece 100. As shown in FIG. 6, after thewidening of the pores shown in FIG. 5, an insulating layer 160 may bedeposited into the pores, filling the space between the sidewalls of theworking piece pore and the previously deposited segments of the fuelcell (120, 130, 140). Thus, FIG. 6 illustrates fabrication operationsfor generating an insulating tube within the pores of the parallel poreworking piece. Delivery functionality may be conferred by having thetube carry therapeutic payloads, for example drugs, cells, geneticmaterial or RNA or siRNA fragments.

In one embodiment of the invention, the insulating tube is generated byplacing a solution of silicon dioxide sol-gel on the open pores of theworking piece, then applying a vacuum to move the sol-gel into the poresof the working piece. The tube 160 is shown in cross section in FIG. 6,however the image is intended to show that the tube surrounds allpreviously grown segments of the fuel cell. The tube is formed from anelectrically insulating material. In one embodiment of the invention,the tube is formed from silicon dioxide deposited from a sol-gel,inserted into the pores by deposition using vacuum pressure.

In accordance with at least one embodiment, the insulating tube 160 maycover the sidewalls of the pores only; alternatively, it may cover moreor less. The sidewalls of the pores are defined as the surfaces of theworking piece which are interior to the pores. Note that the sidewallsof the pores do not include materials 120, 130, 140, 170 that have beendeposited into the pores of the working piece.

The height of the insulating tube 160 may be equivalent to the sum ofthe length of the previously grown layers. Such a height specificationis useful, as an insufficiently tall insulating tube may result in anexposed region of the fuel cell, and thus may result in an electricalshort in the device. It is possible that the insulating tube isdeposited with the assistance of a vacuum, as discussed above. In atleast one embodiment, the material forming tube 160 is a sol-gelformulation of silicon dioxide, as taught by M. Zhang, Y. Bando, and K.Wada in their publication “Silicon dioxide nanotubes prepared by anodicalumina as templates”, in the Journal of Materials Research, Volume15(2), 2000 (incorporated herein by reference in its entirety). In suchan embodiment, silicon dioxide sol-gel may be deposited into the widenedpores 150 of the parallel pore working piece 100 by dipping the parallelpore working piece into a silicon oxide sol-gel, and then applyingvacuum to the particles. Here the application of a vacuum occurs afterthe working piece is dipped into the solution containing the sol-gel. Itis also possible to apply the sol-gel to the open pores side of theworking piece, and subsequently apply a vacuum.

In the fabrication operations at 60, as illustrated in FIG. 6, the roleof applying vacuum is to pull the sol-gel into the pores of thetemplate, as well as to remove the solvent from the solution byevaporation. The solution referred to here is the solution containing asolvent and a solute, the solute being the material that is depositedinto the widened pores of the working piece. A typical sol-gel solutionis composed of silicon dioxide and tetraethyl orthosilicate. Thus, theinsulating layer 160 material may flow around the separator membrane140. The insulating layer 160 may electrically insulate the separatormembrane 140 from the local surrounding environment of the fuel cellparticle.

It is understood that the tube section 160 may function as a carrier oftherapeutic materials, which may enter the tube section in a subsequentoperation instead of proceeding to operation 70.

Fabrication operations may then proceed to 70, as illustrated in FIG. 7,at which a cathode 170 is deposited (deposition), wherein anoxygen-reducing agent is dispersed in a separator membrane material thatallows the passage of glucose but inhibits the passage of oxygenmolecules. FIG. 7 illustrates fabrication operations for performingdeposition of a cathode, wherein an oxygen-reducing agent is dispersedin a separator membrane material that allows the passage of a fuelsubstrate (e.g., glucose) but inhibits the passage of oxygen molecules.

As taught by B. I. Rapoport, J. T. Kedzierski, and R. Sharpeshkar intheir publication “A Glucose Fuel Cell for Implantable Brain-MachineInterfaces,” published in PLoS ONE, Volume 7, Issue 6, June 2012, thismaterial may be a composite of carbon nanotubes and nafion polymer. Theprimary role of this material is to reduce oxygen and allow for thepassage of the fuel molecule, such as glucose.

In accordance with at least one embodiment, the cathode 170 may be acomposite of Nafion/graphene, Nafion/carbon nanotubes, or Nafion/C60(Buckminsterfullerene).

The Nafion/graphene, Nafion/carbon nanotube, or Nafion/C60 composite mayalso be deposited via vacuum-assisted filling into the open pores of theparallel pore working piece 100. In accordance with at least oneembodiment, the parallel pore working piece 100 may be dissolved usingsodium hydroxide at a concentration between 1 mM and 10M. Dissolution ofthe parallel pore working piece 100 may result in free-floatingmicroscale glucose fuel cells.

FIG. 8 shows the fuel cells after being released from the working piece.Etching the working piece releases the particles from the templates.After releasing the particles from the working piece, the particles canbe dispersed in liquids or dried onto surfaces.

In the resulting device, the conducting layers of the anode and cathodemay be separated from the cathode 170 by the separator membrane 140 thatallows for the passage of glucose, but may inhibit the passage ofoxygen. This type of membrane is commonly referred to as a “protonexchange membrane;” at least one embodiment may use the commerciallyavailable product Nafion as the material of choice.

In the disclosed embodiments, glucose may be oxidized at the platinumanode 130 and oxygen may be reduced at the cathode 170. These tworeactions may continue in the presence of a fuel source such as glucose.Nevertheless, in accordance with at least one embodiment, the buildup ofcharge may be accompanied by a resulting electric field.

If a fuel cell's acquired energy is not discharged across a load, thefuel cell may build up electrical charge at the anode and cathode. Ifthe charge is not quenched, it may be used to perform various functionswithin the bodies of humans or other animals. In accordance with atleast one embodiment, this electric field may be used to guide neuronalregrowth, as taught in U.S. patent application Ser. No. 14/874,857,entitled “METHOD AND APPARATUS FOR IMAGE-DIRECTED NERVE GROWTH,” filedOct. 1, 2015 (incorporated herein by reference in its entirety herein)or to otherwise stimulate neuronal or other cells.

In accordance with at least one embodiment, some component of the fuelcell incorporates a sheathing layer or a separate solid segment ofpolypyrrole. Polypyrrole is a biocompatible conductive polymer.Incorporation of a polypyrrole segment may allow for wiring fuel cellstogether, connecting them electrically to each other or to otherentities within humans or other animals. This may allow the fuel cellsto operate in parallel, or in series, with each other or with otherdevices.

In accordance with at least one embodiment, the functional microparticlemay also carry drugs, proteins, nucleic acids, or optically activemolecules. These payloads may be carried on the surface of thefunctional microparticle, adhered via specific binding chemistries.Alternatively, these payloads may be incorporated into the volume ofvarious components of the functional microparticle. The microparticlesmay emit light, for example by connecting the fuel cell to alight-emitting diode, or by carrying luminol or other fluorescentpayloads. This light might be used to activate nerve or other cells.

In one embodiment, the carbon nanotube-nafion composite may include adrug embedded into the volume of the composite. The payload may beloaded into a component of the functional microparticle during theprocess of making the various layer of the microparticle, or it may beinfused into the microparticle after the microparticle has beenassembled and released from the working plate. As an example, thepayload may be loaded into the tube section by immersing themicroparticle in a solution containing the payload. One method ofinfusing a material, such as a polymer, with a payload such as a drug,is to simply store the material in a solution containing a highconcentration of the desired payload.

In accordance with at least one embodiment, the cathode layer may becomposed of carbon nanotubes, graphene, C60, or another materialsuitable for protonation of oxygen to generate water. The carbonnanotubes, graphene, C60, or other material may be filled at anappropriate concentration to ensure the operation of the fuel cell.

The described process is performed on a working piece containing pores.In one embodiment, these pores are cylindrical, parallel to each other,and each has two openings, one on either side of the working piece. Theworking piece has a conductive layer added, sealing all pores on oneside of the working piece. The processes described in this applicationare intended to be performed on the working piece as a whole, meaningthat the process described herein generates one fuel cell for each porein the working piece. As in anodic aluminum oxide working pieces, poredensity may exceed 1 billion pores per square centimeter. Thus, theproposed technique is capable of making at least 1 billion fuel cellssimultaneously.

It should be understood that an electrical storage system may beresident in the same particle as the functional microparticle, forexample in the form of one or more deposited layers comprising acapacitor. An attached storage system may be added in the form of anadditional layer of deposited materials on either ends of the functionalmicroparticle.

It should also be understood that the operations explained herein may beimplemented in conjunction with, or under the control of, one or moregeneral purpose computers running software algorithms to provide thepresently disclosed functionality and turning those computers intospecific purpose computers.

Moreover, those skilled in the art will recognize, upon consideration ofthe above teachings, that the above exemplary embodiments may be basedupon use of one or more programmed processors programmed with a suitablecomputer program. However, the disclosed embodiments could beimplemented using hardware component equivalents such as special purposehardware and/or dedicated processors. Similarly, general purposecomputers, microprocessor based computers, micro-controllers, opticalcomputers, analog computers, dedicated processors, application specificcircuits and/or dedicated hard wired logic may be used to constructalternative equivalent embodiments.

Moreover, it should be understood that control of the fabricationoperations disclosed herein may be provided using software instructionsthat may be stored in a tangible, non-transitory storage device such asa non-transitory computer readable storage device storing instructionswhich, when executed on one or more programmed processors, carry out theabove-described method operations and resulting functionality. In thiscase, the term non-transitory is intended to preclude transmittedsignals and propagating waves, but not storage devices that are erasableor dependent upon power sources to retain information.

Those skilled in the art will appreciate, upon consideration of theabove teachings, that the program operations and processes andassociated data used to implement certain of the embodiments describedabove can be implemented using disc storage as well as other forms ofstorage devices including, but not limited to non-transitory storagemedia (where non-transitory is intended only to preclude propagatingsignals and not signals which are transitory in that they are erased byremoval of power or explicit acts of erasure) such as for example ReadOnly Memory (ROM) devices, Random Access Memory (RAM) devices, networkmemory devices, optical storage elements, magnetic storage elements,magneto-optical storage elements, flash memory, core memory and/or otherequivalent volatile and non-volatile storage technologies withoutdeparting from certain embodiments of the present invention. Suchalternative storage devices should be considered equivalents.

While certain illustrative embodiments have been described, it isevident that many alternatives, modifications, permutations andvariations will become apparent to those skilled in the art in light ofthe foregoing description. While illustrated embodiments have beenoutlined above, it is evident that many alternatives, modifications andvariations will be apparent to those skilled in the art. Accordingly,the various embodiments of the invention, as set forth above, areintended to be illustrative, not limiting. Various changes may be madewithout departing from the spirit and scope of the invention.

As a result, it will be apparent for those skilled in the art that theillustrative embodiments described are only examples and that variousmodifications can be made within the scope of the invention as definedin the appended claims.

We claim:
 1. A method for constructing at least one functionalmicroparticle using a parallel pore working piece, the methodcomprising: constructing the at least one functional microparticle in astructure with defined and parallel, uniform, thin pores that completelypenetrate the structure, wherein the functional microparticle has atleast one dimension less than fifty microns in length, containsmagnetizable material and emits electrical current, electromagnetic orthermal energy, or carries a therapeutic payload, wherein theconstructing further comprises electroplating a conductive initial layerinto the pores of the parallel pore working piece and electrodepositingan anode onto the conductive initial layer prior to performing avacuum-assisted filling, and wherein the functional microparticle isgenerated by a combination of the electrodepositing, an etching of theworking piece, and the vacuum-assisted filling, and results in thefunctional microparticle capable of energy conversion.
 2. The method ofclaim 1, wherein the constructing comprises performing thevacuum-assisted filling of a polymer, ceramic, or composite separatormembrane into the pores of the parallel pore working piece, and onto thepreviously deposited anode.
 3. The method of claim 2, wherein thevacuum-assisted filling is performed by depositing a diluted polymerseparator membrane material into the open pores of the parallel poreworking piece.
 4. The method of claim 2, wherein the etching of theworkpiece comprises widening the parallel pore working piece pores byetching the parallel pore working piece material, and the constructionfurther comprises generating an insulating tube within the pores of theparallel pore working piece, and depositing a cathode after performingthe vacuum-assisted filling.
 5. The method of claim 4, wherein thewidening of the parallel pore working piece pores by etching includesusing an aqueous solution of sodium hydroxide.
 6. The method of claim 4,wherein the insulating tube covers sidewalls of the pores.
 7. The methodof claim 1, wherein the electroplating of the conductive initial layeris performed by electrodeposition implemented by exposing an open poreside of the membrane to an electrolyte and plating materials onto a sideof a metal film at one end of the pores.
 8. The method of claim 1,wherein the constructing further comprises dispersing an oxygen-reducingagent in a separator membrane material that allows the passage ofglucose but inhibits the passage of oxygen molecules.
 9. A method forconstructing at least one functional microparticle using a parallel poreworking piece, the method comprising: constructing the at least onefunctional microparticle in a structure with defined and parallel,uniform, thin pores that completely penetrate the structure, wherein thefunctional microparticle has at least one dimension less than fiftymicrons in length, contains magnetizable material and emits electricalcurrent, electromagnetic or thermal energy, or carries a therapeuticpayload, and further comprising preparing the parallel pore workingpiece for electroplating by applying a micron-thick metal film to oneside of an anodized alumina filter membrane and placing the parallelpore working piece in water so as to wet the pores of the parallel poreworking piece, wherein the resulting particle contains componentscapable of converting energy.
 10. The method of claim 9, wherein thepore wetting process is performed by submerging the entire parallel poreworking piece in water and applying sonication.